Process of producing multilayer color negatives containing masking images for color correction purposes



Aug. 19, 1952 Q HARSH ETAL 2,607,681

' PROCESS OF PRODUCING MULTILAYER COLOR NEGATIVES CONTAINING MASKINGIMAGES F03 CORRECTION PURPOSES Filed March 24, 1950 I EXPOSED AND COLORA DEVELOPED MULT/LAVER NEGATIVE COLOR COLOR FILM IMAGES AND NEGATIVESILVER IMAGES RES/DUAL SILVER HAL/0E S S RGR BASE SELECTIVE E/XAT/ON OFTHE RES/DUAL SILVER HAL/DE IN THE TOP LAYER NEGATIVE COLOR WAGES AND 5NEGATIVE SILVER WAGES RES IDUAL SILVER HAL/DES BASE CONVERSION OF THERES/DUAL SILVER HAL/0E S IN THE TWO LOWER LAYERS TO SILVER IODIDE ORSILVER SULE/DE C NEGATIVE COLOR PoS/r/vE SILVER WAGES AND /J /oD/DE ORSILVER NEGATIVE SILVER /2 SULF/DE MASK/NG WAGES IMAGES /0 BASE DLEAiH/NGF/XAT/ON D l NEG A TIVE COLOR IMAGES POSITIVE SILVER IODIDE OR SILVERSULE/DE MA SKING IMAGES INVENTOR S HAROLD C. HARSH JOSEPH S. ERIEDMA NPatented Aug. 19, 1952 PROCESS OF PRODUCING MoL'rItAYER COLOR NEGATIVESCONTAINING MASK- ING IMAGES FOR COLOR ooRREor oN PURPO SES Harold 'C.Harsh and J osepli S Friedmam Bin g hamton, N. Y., assignors, to GeneralAniline & Film Corporation, New

tion of Delaware York," N. Y., a. corpora- Application March 24,1950,serially 0.151326 1 In Canada May 27 194-777 I 12 Claims. I

This invention relates to color photography, and more particularly to aprocess of producing multilayer color negatives containing maskingimages for color correction purposes.

In the production of color prints from multilayer color negatives, thecolor negative consists of yellow, magenta, and cyan images in thedifferent layers. The cyan image represents the red, the magenta imagethe green, and, the yellow image the blue record of the originalsubject. Color positive prints or transparenciesmay be obtained fromsuch color negatives by direct printing onto a multilayer color positivefilm or paper, or by making color separation negatives which are usedfor making the color positive prints. These color negatives do not as arule completely satisfy the spectral requirements for trichromatic colorreproduction. For instance, the magenta colored image, formed bytheimposition of green light upon the green sensitive layer, records thegreen densities. This image should transmit the blue and the redprimaries, completely. 'To the extent to which it absorbs blue light, itsuperimposes a pattern of the green densities upon the blue, withconsequent color falsification. This color falsification makes itselfmanifest when the color negative is to be printed. That part of theexposure which is due to blue light, and whichshould form a record onlyof the image in the yellow layer in the negative, forms a record of theyellow image admixed with the record of the magenta. The image in theblue sensitive part of the copy material is, therefore, very impure, andserious color degradation results.

It is possible to overcome this defect if procedures are devised toregister a pattern of the magenta dye image, equal in intensity to thedegree to which the magenta dye absorbs blue light, but opposite incharacter, with the yellow dye images. In a similar manner the cyan dyeimage can be corrected for its blue absorption. These masks or modifyingimages can be yellow in color, as suggested by the prior art, or theycan be a neutral gray, composed of dye or silver.

Numerous methods have been proposedv for making corrections in these dyeimages; Generally, these methods are characterized by the fact that themask is on a separate piece of film, and must be registered with theoriginal by manual or mechanical means. This creates problems ofregistry arising from the dimensional variations of film as it ages, andproblems of definitionaristherefore, to have the ing from lack ofoptical contact between original maskintegral with the original. To'accomplish this, it has been pro- .posed to place an auxiliary emulsionlayer within'the pack in which the mask could be formed.

While this gives a desirable result, it introducescomplications into thestructure and the preparationof themonopack material. Since the maskingimageis opposite-in character to the one that it is desiredto modify,emulsions with'special properties have to be used.

To eliminate this. complication, it was proposed in British Patent541,266 to utilize the residual silver halides in the emulsion'after thelatent image has been processed to a dye image, and to convert theresidual halides, after a proper exposure, into a black and white silvermask. The procedure disclosed toaccomplish the for- .mation ,ofa maskwas to treat thefilm after negative color development-in a bleachbath toconvert the silver to silver chloride, to remove .-the silver chlorideby treatment with ammonia oriammonium' sulfite, then .to expose theuntouched residual silver bromide to white light, and develop in an M.Q. developer that yields a silver image. When processed in this manner,there are'formed silver images in each of the layersof the color film.This may be desirable under certain conditions, but for certain purposesthe presence of a mask representing an image ofthe yellow dye pattern isharmful and undesirable. This was recognized by the British patentee andhe specifically states in his specifications that the bleach, to be usedto effect a conversion. of. the silver to silver chloride, be of P sucha mild nature that it does not destroy the colorsensitivities of thegreen and red sensitive layers. After treatment with such a mild bleachsolution, it becomes possible to selectively expose the red and/or greensensitive layers, sothat masking images be formed only in theseparts.

The restriction that a bleach be used that is so mild that it does notdestroy the color sensitivity of the green and red layers, severelylimits the operator using the material and the-manufacturer who makesit. The patentee cites a number of sensitizing agents that could beused, which will notice destroyed by the extremely mild agentshe-mentions. But, generally, subjecting an optically sensitized film tothe action of an oxidizing agent reduces the color sensitivity of thatmaterial almost to the vanishing point. To

4 the green and red sensitive layers to silver iodide or silver sulfide.

, 6. Conversion of the negative and any other colloidal silver to 'asilver halide or ferrocyanide. 7. Fixation of all reformedsilver saltsin the Other objects and advantages of this invention will be apparentby reference to the foregoing specification, in which its preferreddetailsand 7 embodiments are described.

The foregoing objects are accomplished fixing an exposed and developedphotographic color negative film for a period of time ranging from /g to2 minutes, in a bath consisting of the following composition:

, Grams Ammonium or sodium thios'ulfate 100 Sodium sulfate 100 Water tomake 1 liter.

All of the silver halides remaining in the uppermost (blue sensitive)layer are removed, leaving intact the silver halides in the other twolayers. The sodium sulfate reduces 'the'penetrm tion of the thiosulfateand limits its action to the uppermost layer. The fixed film is thenwashed with water. a Q I It is now possible to effect a non-colorselective masking image in the cyan and magenta layers by bathingthefilmin an aqueous solution of potassium' or sodium iodide. This solutionconverts the residual'silver halides in the green and red sensitivelayers intosilver iodide, which will act as a mask. To achieve a moreopaque image, the iodide bath may be replaced by a sulfide bath of thetype used to form silver sulfide'images, such 'as a 1% solution ofsodium sulfide. After conversion to iodide or sulfide, the 'film istreated with a solution or solutions that will convert the silverpresent in the negative, filter, or anti-halation layer, to a form whichis soluble in hypo, so'that salts like silver ferrocyanide, silverchloride or bromide can be readily removed before any action on theiodide or sulfide'becomes evident. A bleach bath such as:

V Grams Potassium ferricyanide 40 will convert the silver to silverbromide without affecting either silver iodide or silver sulfide to ualhalides in the top or blue sensitive layer of the film.

5. Conversion of theresldual silver halides in 8. Washing and drying.The foregoing description of our invention will "be'more apparent fromthe following examples whichare set forth merely to illustrate theinvention and should not be construed as a limitation thereof.

- Example I A multilayer photographic color film such as preparedaccording to United States Patents 2,186,849; 2,220,187, and 2,357,388,was exposed to a colored object and thendeveloped for 15 minutes in acolor developer of' the following composition:

7 v V Grams Diethylamiuo aniline 51.5 2-amino-5-die'thylaminotoluenemono l-ICL; 'lgO Sodium sulfite 0.5 Sodium carbonate 67.5 Potassiumbromide 2.5 Hydroxylamine HCl 0.5

Water to make 1 liter.

This development resulted'in the formationof negative silver and colorimages atthe exposed portions of the multilayer film. The colordeveloped film was then shortstopped in a 1% solution of acetic acidcontaining 1% sodium acetate, washed for 10 minutes, and then fixed for1 minutes in a solution of the following composition: I I I V GramsSodium thiosulfate "a 1001 Sodium sulfate (dehydrated) 10 Water to make1 liter. I

By this fixing treatment the residual silver halides in the'uppermostblue sensitive layer were removed. The silver halides in the remaininglayerswere not materially affected. In this fixing bath the function ofthe sulfate is to prevent the rapid diffusion of the fixing bath intothe depth ofthe film. Any other agent, such as alcohol, glycerin, sugar,etc, which function in like manner, can be used. a

The film was washed in running water for 10 minutes to remove excessivefixing bath, and then subjected to the action'of a l solution ofpotassium iodide, for a period of 10 minutes. In this treatment, thepositive silver halide images present in the cyan and magenta layerswere converted into silver iodide, which is stable and nonsensitive tothe action of light.

All the metallic silver present in the various layers was then convertedinto a silver salt, such as silver ferrocyanide, bythe action of a 10%solution of potassium ferricyanide. Instead .of employing aqueoussolutions of potassium ferricyanide, as the oxidizing agents, othersolutions of the commonly known oxidizing agents which convert thesilver to a silversalt other than silver iodide, may be used, such as,for example, ferric chloride, copper sulfate in the presence of bromideor chloride ions, and the like. The bleached film was washed in runningwater for several minutes and treated with a' normal fixing bath for 5minutes, washed, and then dried.

In the normal fixing bath, the rate of fixation of the silver salts,such as silver .chloridasilver bromide, silver ferrocyanide, and thelike, is so muchgreater than thedissolution of silver iodide that to,allintents and purposes, the action can'- be considered as'afiectingonly the silver chloride,

silver bromide 'andsilver ferricyanide, thus leavingthe silver-iodideimage -substantially unimpaired} ,By thismeans, the'silveriodidepositive I Example [I I I Example I was repeated with theexception that after color development, the film was further developedina non-staining black and white developer such as; v

1 Grams Pyrogallic acid 5 Sodium sulfite 30 Sodium carbonate 10,Potassium bromide 2 Water to make 1 liter. I

or any other known non-staining black and white developer. Thisdevelopment was carried on togamma infinity (the highest obtainablecontrast of a 'film) so that all exposed silver halide grains weredeveloped. I

The colored and black and white developed film was then differentiallyfixed and processed through to completion in the manner set forth inExample I. This procedure has the advantage over the procedure inExample I in that it "removes all danger of having a residual negativesilvei 'image developed in the final or masking development, since allsilver halide unexposed intheffirs't exposure, is exposed and convertedt metallic silver thereby.

, v I Example III 1 Example I was repeated with the exception thata.0.5% solution of sodium sulfide'was used in place of potassium iodide:The masking image obtained showed a" greater opacity. 7

' Example IV I r r Example II was repeated withgthe exception thata-1.5% solution of sodium sulfide was used in place of potassiumiodide.- In the accompanying drawing," the :figure-is'a flowdiagramrepresenting enlarged'sectional. views -of a film showing the method offorming a masked :image according to our invention. Views A, B, C, and Dof the figure illustrate the changes taking-place in the film during thvarious steps of processing.

As shown in the figure, i0 is a transparent base or support havingsuperposed thereon, layers-l I, I2, and M containing cyan, magenta andyellow color images, respectively.- Layer l3 representsa filter layer. I7

A illustrates a section of the multilayer color film which has beenexposed and color developed. B illustrates the same multilayer colorfilm after the residualsilver halide in the toplayerhas been removed byselective fixation. t 0 illustrates the same multilayer'color film afterthe conversion of the residual silver halides in the'twolower layers tosilver iodideor silver- ,1) illustrates the same multilayer color filmafter bleaching and fixation.

3 It will be noted that masking images consist-- ing. of silver iodideor silver sulfide are only formed in the magenta and cyan layers. s

6 Obviou'sly,the practice of the presentinven tion is not to be limitedto the processing of multi-.. layer photographic color fil'm of thetype. set: forth intheiexamples. Multilayer photographic film suchasprepared-according to United States Patents 2,269,158; 2,266,443; 2,272,191;;-2,284,877;. 2,289,803; 2,304,940; 2,311,020 2,350,380;;-2,397,-.864-5-6 and 7, and the like,'can also .beqprocessed into colornegatives-containing maskingimages, in accordance with the presentinvention. .Vari ous other modifications will occur to those skilled intheart which, however, do not depart from: the spirit and nature of thisinvention, and wedonot intend: to be limited in the patent granted,

except as required by-the prior-art and in the: -following claims. a j rv This application .is a continuation-dn-part: of our application SerialNo. 703,480, filed on October 16, 1946. V

We claim: -1. -I n theproduction of subtractively colored, negativeswith correction printing masks -,;integra-lly bound therein, formultilayer, fi lrrr -l ia ving silver halide emulsions containingf colorformers and being respectively sensitized to the blue, green, and redregions of the spectrum, ;by-

exposing said multilayer film to a colored objectv and color developingthe same, theimprovement.

which comprises selectively fixing the residual.

silver halides in the blue sensitive layer, converting the residuallight sensitive silver halidesin the other emulsion layers into lightinsensitive silver salts selected from the group consisting of silveriodide and silver sulfide, and removing all metallic silver. v

In the production of subtractively colored negatives with correctionprinting masks, integrally bound therein, for multilayer film havingsilver halide emulsions containing I color, formers and beingrespectively sensitized to th e blue, green, and red regions ofthe-spectrum,- ,by. exposing the said multilayer film to a coloredobject and color developing the same, the improve: ment which comprisesselectively fixing the re-, sidual silver-halides in the blue sensitivelayer, converting the residual silver .halides'to silver iodide in themagenta and cyan layers, convert-- ing all 1 metallic silver to a silversalt soluble in hypo, and treating the film with hypo to remove thesilver-salt thus. formed.= U

3..In the production of subtractivelylcolored negatives with correctionprinting masksjin tegrally bound therein, for multilayer film havingsilver halide emulsion ,containing color formers and being respectivelysensitized to the) blue, green, and red regions of the spectrumJbyexposing the said multilayer film to a colored object and colordeveloping thesame, the im provement which comprises selectively fixingthe residual silver halides in the blue sensitive layer, converting theresidual silver halides in the other emulsionlayers'to silver sulfide,converting all metallic silver to a silver salt removable byjhypo, andtreating the film with hypo toremove the: silver salts thus formed. I f

4. In the production of subtractive'ly colored negatives with,correction printing masks,.' in.- tegrally bound therein, for multilayerfilm having silver halide emulsions containing color formers and beingrespectively sensitized to the blue," green, and red regions of thespectrum, by exposing the said multilayer film to a colored object andcolor developing the same, the improvement which comprises developingthe .said color (1&1. veloped filmin a non-staining developer incapable.

of coupling withthe colorformer'in thela'yer,

the'group consisting of'silver iodide and silver Sulfide, converting allmetallic silver to a silver salt soluble in hypo, and treating thefilm-with hypoto remove the silver salt thus formed.

In the production of subtractively colored negatives iwith correctionprinting masks, integrally bound therein, for multilayer film havlngsilver halide emulsions containing color formers and being respectivelysensitized [to the'blue, green, and red regions of the spectrumybyexposing the said multilayer film to a colored object and'colordeveloping the same, the improvement which comprises developing the saidcolor developed film in a non-staining developer incapableof-coupling'with the color former in the layer, for atime sumcient tobring the development to gamma infinity, selectively fixing the residualsilver halides in the blue sensitive layer, converting the'residualsilver halides in the magenta and cyan layers, to silver iodide,converting all metallic'silver to a silver salt soluble in hypo, andtreating the film with hypo to remove the silver salt thus formed. r

6. I n the production of subtractively colored negatives with correctionprinting masks; in tegrally bound therein, for multilayer film havingsilver halide emulsions containing color formers and being respectivelysensitized to the blue,

green, and red regions of the spectrinn, by exposing the said multilayerfilm to a colored object and color developing the same, the improvementwhich comprises developing the said color] developed film in anon-staining developer incapable of coupling with said color formers,for a time suificient to bring the development to gamma infinity,selectively fixing the residual silver halides in the blue sensitivelayer, convert-- ing the residual silver halides to silver'sulfide,converting the metallic silver'in all layers to a hypo soluble silversalt, and treating the film with hypo to remove the silver salt thusformed. o 7. In the production of subtractively colored negatives withcorrection printing masks, in tegrally bound therein, for multilayerfilm having silver halide emulsions containing color formers and beingrespectively sensitized to the blue, green, and red regions of thespectrum, by exposing the said multilayer film to a colored object andcolor developing the same, the improvement, which comprises developingthe said color developed film in a non-staining developer incapable ofcoupling with, said color formers, for a time sufl'icient'to bring thedevelopment to gammainfinity, selectively fixing the residual silverhalides in theblue sensitive layer with an aqueous solution containinghypo and a member selected from the class consisting of alkali sulfates,water miscible alcohols, sugar, and glycerin, andtconverting theresidual light sensitive silver halides inethe other emulsion layersinto alight 'insensitive form by treating with a memberselected from theclass consisting of aqueous solutions alkali sulfides" and alkaliiodides.

8. In the production of subtractively colored negatives with correctionprinting masks, integrally bound therein, for multilayer film havingsilverhalide. emulsions containing color formers and being respectivelysensitized to the blue green, and red regions of the spectrum, byexposing the said multilayer film to a colored object and colordeveloping the same, the improvement which comprises developing the saidcolor developed film in a non-staining developer incapable of couplingwith said color formers, for a time sufficient to bring the developmentto gamma infinity, selectively fixing the residual silver halides in'theblue sensitive" layer, with an aqueous solution containing hypo andsodium sulfate and converting the residual light sensitive silverhalides in the other emulsion layers into a light insensitive formbytreatment with an aqueous solution of potassium iodide.

9'. In the production of subtractively colored negatives with correctionprinting masks, integrally bound therein, for multilayer film havingsilver halide emulsions containing color formers and being respectivelysensitized to: the blue, green, and red regions of the spectrum, byexposing the said multilayer film to a colored object and colordeveloping the same, the improvement which comprises selectively fixingthe residual silver halides in the blue sensitive layer, converting theresidual silver halides in the other emulsion layers to aninsolublesilver salt selectedfromthe class consisting of silver iodideand silver sulfide, and removing all developed silver by bleaching andfixing to produce positive silver images inthe magenta and cyan layers.

10. In the production of subtractively colored negatives with correctionprinting masks, integrally bound therein, for multilayer film havingsilver halide emulsions containing color formers and being respectivelysensitized to the blue, green, and red .regionsof the spectrum, by ex:posing the said multilayer film to a coloredobject and color developingthe same, the improvement which comprises selectively fixingthe residualsilver halides in the blue sensitive layer, converting the residualsilver halides in the magenta and cyan layers to silver iodide bytreatmentwith an aqueous solution of potassium iodide, converting allmetallic silver into. silver ierrocyanide with an aqueous solutionofpotassium ferricy'anidepand treating the film with hypo to remove thesilver ferrocyanide thus formed.

11; In theproduction of subtractively colored negatives with correctionprinting masks, 111- tegrally bound therein, for multilayer film havingsilver halide emulsions containing color formers and being respectivelysensitized to the blue, green, and red regions of the spectrum, byexposing the said multilayer film tov a colored object and colordeveloping the same, the improvement which comprises selectively fixingthe residual silver halides in the blue sensitive layer with an aqueoussolution containing hypo and sodium sulfate, converting the residualsilver halides to silver sulfide by treatment with an aqueous solutionof sodium sulfide, oxidizing all metallic silver with an aqueoussolution of potassium ferricyanide,

and treating'the film with hypo to remove the HAROID C. HARSH. JOSEPH S.FRIEDMAN.

' 1o REFERENCES CITED The following references areof record in the fileof this patent:

5 UNITED STATES PATENTS Number Name Date 2,203,653 Evans June 4, 19402,431,996 Duerr et al .d Dec. 2, 1947 2,476,541 Friedman July 19, 1949FOREIGN PATENTS Number 7 Country Date 517,020 Great Britain Jan. 18,1940 541,266 Great Britain Nov. 20, 1941

1. IN THE PRODUCTION OF SUBTRACTIVELY COLORED NEGATIVES WITH CORRECTIONPRINTING MASKS, INTEGRALLY BOUND THEREIN, FOR MULTILAYER FILM HAVINGSILVER HALIDE EMULSIONS CONTAINING COLOR FORMERS AND BEING RESPECTIVELYSENSITIZED TO THE BLUE, GREEN, AND RED REGIONS OF THE SPECTRUM, BYEXPOSING SAID MULTILAYER FILM TO A COLORED OBJECT AND COLOR DEVELOPINGTHE SAME, THE IMPROVEMENT WHICH COMPRISES SELECTIVELY FIXING THERESIDUAL SILVER HALIDES IN THE BLUE SENSITIVE LAYER, CONVERTING THERESIDUAL LIGHT SENSITIVE SILVER HALIDE IN THE OTHER EMULSION LAYERS INTOLIGHT INSENSITIVE SILVER SALTS SELECTED FROM THE GROUP CONSISTING OFSILVER IODIDE AND SILVER SULFIDE, AND REMOVING ALL METALLIC SILVER.